87 GMC Sierra 1500 valve cover wrestling match

[nuckollsr]

Have '87 GMC my dad bought new and willed to us in 2007 with 32K on it. It's the 4.3L v6. Runs great, engine was hardly broken in yet. 35K later, we've been wrestling with stuff that 'ages' . . . gaskets, hoses, etc. In spite of having been replaced in a shop about 3 months ago. Driver side valve cover has been leaking prodigiously Decided to tackle it my self.

Was dismayed by the amount of 'stuff' that had to be removed to get the cover off. Most of the a/c compressor brackets have been removed (need to replace the compressor anyhow so that's not a big deal). However, I find that the cover cannot be removed without disconnecting a hard-line threaded into the left-forward corner of the carburetor base . . . vacuum line to brake servo? Seems to disappear into that region.

I find that the fitting is, shall we say, unwilling to loosen gracefully. I'm soaking it with a good nut-cracker juice. Now I'm wondering how the mechanic got the new gasket installed a few months ago. It appears that the cover cannot be removed for service without opening that joint in the plumbing . . . yet it seems that the joint has not been opened for a very long time . . . I tried contacting the mechanic that did the work last time . . . doesn't work there any more.

Is there some non-obvious, magic move outside the experience set of an airplane electron herder for getting this cover off? I'm frustrated that what should be a one-hour task is turning into an exercise in fits and starts that may take days!

Living out in the hinterlands suggests that I need to get more up-close and personal with my truck. So while I'm waiting for the nut-cracker juice to work its magic, I thought I would seek membership in and the counsel of folks who have been-there, done-that.

Thanks!

Bob . . .

[Nontwisty396]

I had a similar problem on a truck I worked on a while back. I ended up taking the carb bolts out far enough to raise the carb to get the valve cover clearance I needed. Of course then I had to replace the carb base gasket, but that was nothing compared to the potential time lost trying to remove the fitting...
May not be the solution you wanted, but it might work in a pinch...
If you have any brake line wrenches, they work well on basically any pipe fitting on your rig.

[nuckollsr]

This hard-line goes into the manifold under the carb.

It is indeed the vacuum line for the brake booster. It routes tightly along the upper lip of the valve cover basically trapping it against the rockers. I can't get onto it with a really good wrench . . . and I'm leery of 'wiping the tops off' the hex fittings with a two-faced engagement. I've just about decided to cut the tube with sufficient length to add a hose-barb to the stub. The remains can then be sucked out with a 6-point socket on and extension . . . or even an impact wrench.

The hard line coverts to hose anyhow at the back of the engine at what appears to be an inline filter of some kind. Making that entire run with hose seems a practical modification.

This discovery may explain why the previous attempt to do a righteous gasket installation fell short. If he didn't open that line, then the new gasket had to be weaseled under the cover while still captive between the vacuum line and the rockers. Getting that line out of the way seems critical to doing a good gasket installation. Replacing the line with hose seems a low-risk alternative to buggering up some fittings.

Thanks for your interest and input.

[Nontwisty396]

Oh, I see it goes into the intake manifold. I was picturing it going into the carb base. WHOLE different story.
If you cut the line and use rubber hose make sure it's not thin wall hose or it will collapse under vacuum.
You may have enough room to use a brake line wrench, they are like a box end with a slot to slide over the line, and they grip on 4 sides instead of 2. May have to use a wrench on the fitting at the manifold to help loosen the line nut and avoid twisting the pipe.
Another trick is to tap (lightly!) on the line and the fitting to help break them loose easier...

[nuckollsr]

Yeah, got my tongue tangled around my eyeteeth and couldn't see what I was saying. After I cut the tube, it deflected enough to remove the cover. Got the cover and silicone gasket de-greased and bonded the gasket to the cover with RTV. I'll let the RTV cure overnight and put the cover back on in the morning.

After cutting the tube, it was obvious that I didn't need to wrestle the fitting out of the manifold. Once the cover is replaced, I can slip a hose-splice secured with two clamps over the gap in the tube. Hope this puts my oil leaks to bed for a time . . . got an a/c compressor to wrestle with next!

[87 STEPPER]

Originally Posted by nuckollsr

Is there some non-obvious, magic move outside the experience set of an airplane electron herder for getting this cover off? Bob . . .

Yep call a A&P to remove it for ya! Man I can't believe you haven't thought of that by now! You Sparkies never remove or replace your now panels how is this any different? LOL Sorry Bob I couldn't resist F'n with you.

If you are still fighting this very simple task and losin' try a BURNZ-O-MATIC Torch heat the manifold fitting only its aluminum and it will expand faster than the steel B nut on the hard line hold the manifold fitting with a wrench and turn the steel B nut in the tighten direction first then loosen it.

And as mentioned before it is recommended that you use some line wrenches.

Good luck.

Oh yeah Welcome to the board.

[nuckollsr]

Touche' my friend. I don't have a set of tube wrenches . . . but never met a tool I didn't like. Might pick up a set next trip to Wichita.

In the mean time, a more drastic move (cut the line) got the cover off, cleaned, gasket bonded and replaced in good form. I really DO like those valve covers. Three, centrally located hold-down screws that tighten up against internal spacers. The last time I fought a cover leak was on a Chevy straight 6. Tightening those cover screws correctly was like learning to play violin . . . and it was before silicone gaskets.

I'll put a short piece of 3/8 hose on the tube to restore brake vacuum.

My next step is to put all that compressor support bracketry back on, install new compressor, suck down the system and recharge it. Summer is just getting warmed up here in KS . . . I really don't enjoy the Model 270 a/c (2 windows down, 70 MPH) . . . it blows my cowboy hat off.

This is a really cool forum . . . I'll be replacing a dash cover next after refurbishing the vacuum operated, HVAC doors . . . but not until the weather cools off. I'll be back to bug you guys again then.

See http://aeroelectric.com

That's what I do in my parallel universe . . . if you've got any DC power system issues, I herded electrons on airplanes for 45 years before retiring to cow, oil, wheat and cotton country. Here's #5 grandson getting a driving lesson in his great-grandpa's 87' GMC.

http://tinyurl.com/jhmwbxe

Maybe he can drive it on his first date . . .

Thanks!